The SunSDR2 PRO is the latest transceiver from Russian company, Expert Electronics, and packs a lot of features into a very compact form factor.

All the HF amateur bands are included plus VHF coverage of the 50MHz and 145MHz bands. HF output power is 15 watts, reducing to 7 watts on the VHF bands.

The receiver architecture employs 16-bit digital down conversion (DDC) with 14-bit Digital Up Conversion (DUC ) used for the transmitter. Just to complete the package, it uses a standard Ethernet or optional Wi-Fi to connect to the host PC so has remote operation potential. COMPREHENSIVE CONNECTIONS.

Despite the small size of the SunSDR2 PRO, it includes a wide range of external connections. The front panel, see Photo 1, has two standard 6.25mm (1/4”) jacks for phone and microphone respectively plus a Mic 2 socket that takes a standard Yaesu MH-31 style RJ-45 connector.

Moving round to the rear panel, Photo 2, there is a 4-pin Molex latching power socket that is used with the supplied power lead to connect to the shack’s 13.8V supply. Unusually, the SunSDR2 PRO can be powered by up to 16V DC if you want to squeeze the last few watts from the PA. Maximum current consumption is 5A.

The Ethernet connection uses a standard RJ-45 connector and runs at 100Mb/s, whilst the antenna connection is via three mini-UHF connectors, one for VHF and the other two for HF. As these are an unusual choice, the SunSDR2 PRO included a short mini-UHF to SO-239 patch lead that enabled me to get on the air quickly. There were two more 6.25mm jacks on the rear panel used for a Morse key and external PTT control respectively.

For those wanting to use the SunSDR2 PRO with an external PA there was a phono socket that carried the all-important ALC line. The SunSDR2 PRO is ready to link with a wide variety of external devices thanks to the provision of a 15-pin Ext Ctrl connector of the rear panel.

This ‘D’ type connector carries a power supply feed along with 8 open-collector outputs that can be programmed to switch as you change bands. In addition to all the essential connections, the SunSDR2 PRO provides some interesting advanced features. For those requiring very tight frequency accuracy there was an SMA socket that accepted a 10MHz external reference at CMOS level input.

This was ideal for connecting a GPS disciplined oscillator. The ‘ADC in’ socket provided direct, unfiltered access to the input of the SunSDR2 PRO’s high speed ADC. This opens-up the possibility of using the SunSDR2 PRO in under-sampling mode to cover any band up to the 700MHz limit of the ADC.

Similarly, there was an unfiltered DAC out for the transmit side. Lastly, there was an Rx out jack that provided an output from the SunSDR2 PRO’s front end filters immediately prior to the ADC. This could be...